BELO HORIZONTE, Brazil, Feb 1 (Reuters) - All evidence suggests that Brazilian miner Vale’s deadly dam burst was caused by liquefaction, the same issue that led to the 2015 collapse of the Samarco dam which is co-owned by the company, a Minas Gerais state official told Reuters.

Liquefaction is a process whereby a solid material such as sand loses strength and stiffness and behaves more like a liquid. It is a common cause for the collapse of dams holding mining waste, known as tailings, because the walls of these dams are mostly built with dried tailings which consist of a mixture of sand and clay-like mud. (Reporting by Marta Nogueira; Editing by Christian Plumb)